Caption: Peculiar galaxy. Optical image of the core of peculiar galaxy NGC 4438, or Arp 120. The pink structure is a giant bubble of gas thrown off by a supermassive black hole at the galaxy's core. Stars near the centre (blue) are partly obscured by thick lanes of dark dust. NGC 4438 is about 50 million light years from Earth in the constellation Virgo. This image was made using the Wide Field and Planetary Camera 2 (WFPC2) on the Hubble Space Telescope.